There are currently large numbers of wheelchair bound individuals, throughout the world, who would realize health benefits through increased exercise. These groups include, but are not limited to, the paralyzed, stroke victims, amputees, the aged, and those with cerebral palsy. These people to a large extent must rely on a wheeled device such as a wheelchair for effective mobility. This type of transportation typically fails to promote any exercise or movement of the handicapped limbs which leads to varied medical problems. Increased exercise would decrease the incidence of muscle atrophy, osteoporosis, venous stasis (poor circulation), decubitus ulcers (bed sores), and stiffening of joints. In this regard it should be noted that muscular atrophy is due to the lack of muscle activity. Similarly, the incidence of osteoporosis is also increased as a result of disuse of a limb. Venous stasis is due to the lack of muscle contractions. In a healthy limb continuous contraction of the muscle helps push the blood through the circulatory system. This is especially important in the lower limbs and the lack of muscle contractions is why the blood tends to pool in the feet and ankles of paralyzed persons leading to swelling. Decubitus ulcers are the result of pressure points (i.e., between a bone and a bed or seat) which stops the flow of blood to part of the tissue. (In a healthy person, fidgeting keeps such problems from developing.) The lack of circulation tends to lead to a breakdown of the tissue and often infection. Finally, stiffening of the joints also results from disuse of a limb. Exercise would also lead to cardiovascular conditioning and an overall increase in the quality of life. Cardiovascular deconditioning is the result of inadequate exercise and this inadequacy is due to the limited muscle mass available in the arms which inherently limits our cardiovascular exercise capability to two-thirds that of our leg cardiovascular exercise capability.
In summary it should be noted that if an individual is confined to a wheelchair and does not get proper exercise the body will deteriorate. The effect on the mental health of a person with paralysis who is slowly watching his or her body deteriorate is obviously of importance. Their efforts to maintain a positive outlook would be helped by keeping the paralyzed limbs in good shape. This would also aid in full recovery if a treatment is ever developed for the cause of their paralysis. For a person without paralysis, normal walking is sufficient to avoid experiencing any of the above symptoms.
The need for exercise has long been recognized and many differing designs have been proposed in recognition of this need. U.S. Pat. Nos. 4,316,616 and 4,471,972 have both proposed exercising attachments which can be added to the front of a wheelchair which will provide for rotational movement of the arms while at the same time causing the wheelchair to be propelled in a forward direction. U.S. Pat. Nos. 4,572,501 and 4,824,132 additionally teach not only rotational movement of the arms but also rotational movement of the feet to provide for suitable exercising, the rotational movement of the feet being achieved through a normal bike-pedal mechanism. In the four designs mentioned above, there is an insufficiency of exercising of the arms by the crank-type mechanisms illustrated. The first two patents do not teach any exercising for the legs and while the second group achieves desirable leg exercising, they do it in devices which must be disconnected from a wheelchair before the patient can be transferred to or from the wheelchair. None of the foregoing patents disclose exercising of the arms where there is almost full extension and retraction of the arms, which is considered a better form of exercise.
A large number of patents show lever devices which can be mounted on wheelchairs of either a conventional design or of a special design. These levers have an upper handgrip portion and are pivotally interconnected to the wheelchair at their lower end. In operation, these levers can be pivoted from a forward arm extended position to a retracted arm position to provide for forward movement. Representative U.S. Pat. Nos. are: 4,840,076; 4,811,964; 4,762,332; 4,735,431; 4,560,181; 4,506,900; 4,503,724; 4,453,729; 4,358,126; 4,354,691; 3,994,509; 3,877,725; 3,666,292; 2,643,898, 2,578,828; and 838,228.
All of the patents mentioned in the previous two paragraphs have various design defects, some requiring chairs of special design, and others requiring substantial modification to existing chairs. Others do not maintain bilateral motion of the arms and legs. Many designs do not permit the normal lateral transfer of the occupant to and from the wheelchair.